1. Field of the Invention
The present invention relates to a method for positioning an ink cartridge when the ink cartridge is mounted on an ink jet recording apparatus, and the ink cartridge and ink jet recording apparatus used for such method.
2. Related Background Art
Regarding the structures whereby to position a detachably mountable ink cartridge in a given position for an ink jet recording apparatus, there have been known the ones such as disclosed in Japanese Patent Laid-Open Application No. 63-15752 and Japanese Patent Laid-Open Application No. 59-12855.
FIG. 6 is a view which schematically shows a structure for positioning an ink cartridge according to the prior art disclosed in the Japanese Patent Laid-Open Application No. 63-15752. FIG. 7 is a view which schematically shows a structure for positioning an ink cartridge according to the prior art disclosed in the Japanese Patent Laid-Open Application No. 59-12855.
The structure for positioning the ink cartridge shown in FIG. 6 is arranged to supply ink from each ink supply port 65 of the cartridge case 63 through the plug of each ink cartridge 61. Here, the positioning pin 62 provided for each ink cartridge 61 is inserted along each positioning groove 64 arranged for the cartridge case 63. Then, in positioning the needles 66 of the cartridge case 63 at the plug of the ink cartridge 61, the needle 66 is made to penetrate through into the plug.
The structure for positioning the ink cartridge shown in FIG. 7 is arranged so as to allow the ink cartridge 71 to be inserted for fitting it over a supply tube 73 to supply ink into an ink tank 72, thus positioning the ink cartridge 71 and also, preventing ink leakage from the ink cartridge 71.
However, the following problems are encountered in positioning the ink cartridge according to the prior art.
The pointed end of the needle that conducts ink from the ink cartridge into an ink jet head is sharp and dangerous according to the prior art disclosed in Japanese Patent Laid-Open Application No. 63-15752. To counteract this, it may be possible to adopt a tube like a pipe whose pointed end is not so sharp as that of the needle. In order to make it easy for such tube to penetrate the plug of the ink cartridge, a prepared hole may be provided for the plug. Even if such a countermeasure should be taken, it is not easy to make the tube penetrate the plug or, in some cases, it becomes impossible for it to penetrate the plug should there be any misregisteration between the prepared hole of the plug and the tube.
Also, for the prior art disclosed in Japanese Patent Laid-Open Application No. 59-12855, only an ink supply tube is prepared for supplying ink to an ink tank when the ink cartridge is mounted. As a result, the fitting portion arranged for mounting the ink cartridge is under the so-called shadow of the user's own hand, making it difficult to perform the required mounting operation. To counteract this, it is conceivable that a guiding portion is arranged on the periphery of the ink cartridge or the like so that the ink cartridge is guided to the fitting portion arranged for the cartridge to be mounted exactly at the end.
However, with such structure arranged as above, it is required to enhance the precision of processing dimensions of the ink cartridge considerably in addition to the provision of the guiding portion to fit the ink cartridge with the ink supply tube assuredly. Therefore, the fitting portion of the ink cartridge is rigidly restricted even after the ink cartridge and ink supply tube are positioned by fitting them together. This restriction may lead to exerting a load on the supporting portion of the ink supply tube or the like. Therefore, this arrangement is not preferable if a frequent exchange of ink cartridges should be taken into account. Meanwhile, it is possible to avoid such exertion of load as described above if the gap between the guide portion and ink cartridge is made larger, for example. This may also ease the required precision of the processing dimensions. In this case, however, the ink cartridge cannot be guided assuredly to the portion where it is fitted finally, thus making it difficult to execute any exact fitting after all. Moreover, if the posture of the ink cartridge is tilted by the hand of operator or the like when mounting it, the larger gap allows it to be inclined easily, leading to the exertion of a load to the supply tube or the supporting portion of the supply tube eventually.